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What's powering Britain right now
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Carbon intensity is a measure of how much CO2 is released for every unit of electricity generated — expressed in grams of CO2 per kilowatt-hour (gCO2/kWh). When the grid runs on wind, solar, hydro and nuclear, intensity is low. When gas and coal pick up the slack, it rises.
The figures shown here come from the National Grid ESO Carbon Intensity API, which is updated every 30 minutes and includes forecasts for the next 48 hours.
Why time-shifting matters. If you can run heavy appliances — dishwasher, washing machine, EV charger — during the greenest window of the day, the same task produces less CO2. The grid does the cleaning; you choose when.
The band thresholds (very low, low, moderate, high, very high) come from the API itself and are updated by National Grid ESO as the grid decarbonises over time.